( function () {
class Reflector extends THREE.Mesh {
  constructor(geometry, options = {}) {
    super(geometry);
    this.type = 'Reflector';
    const scope = this;
    const color = options.color !== undefined ? new THREE.Color(options.color) : new THREE.Color(0x7F7F7F);
    const textureWidth = options.textureWidth || 512;
    const textureHeight = options.textureHeight || 512;
    const clipBias = options.clipBias || 0;
    const shader = options.shader || Reflector.ReflectorShader; //

    const reflectorPlane = new THREE.Plane();
    const normal = new THREE.Vector3();
    const reflectorWorldPosition = new THREE.Vector3();
    const cameraWorldPosition = new THREE.Vector3();
    const rotationMatrix = new THREE.Matrix4();
    const lookAtPosition = new THREE.Vector3(0, 0, -1);
    const clipPlane = new THREE.Vector4();
    const view = new THREE.Vector3();
    const target = new THREE.Vector3();
    const q = new THREE.Vector4();
    const textureMatrix = new THREE.Matrix4();
    const virtualCamera = new THREE.PerspectiveCamera();
    const parameters = {
      minFilter: THREE.LinearFilter,
      magFilter: THREE.LinearFilter,
      format: THREE.RGBFormat
    };
    const renderTarget = new THREE.WebGLRenderTarget(textureWidth, textureHeight, parameters);

    if (!THREE.MathUtils.isPowerOfTwo(textureWidth) || !THREE.MathUtils.isPowerOfTwo(textureHeight)) {
      renderTarget.texture.generateMipmaps = false;
    }

    const material = new THREE.ShaderMaterial({
      uniforms: THREE.UniformsUtils.clone(shader.uniforms),
      fragmentShader: shader.fragmentShader,
      vertexShader: shader.vertexShader
    });
    material.uniforms['tDiffuse'].value = renderTarget.texture;
    material.uniforms['color'].value = color;
    material.uniforms['textureMatrix'].value = textureMatrix;
    this.material = material;

    this.onBeforeRender = function (renderer, scene, camera) {
      reflectorWorldPosition.setFromMatrixPosition(scope.matrixWorld);
      cameraWorldPosition.setFromMatrixPosition(camera.matrixWorld);
      rotationMatrix.extractRotation(scope.matrixWorld);
      normal.set(0, 0, 1);
      normal.applyMatrix4(rotationMatrix);
      view.subVectors(reflectorWorldPosition, cameraWorldPosition); // Avoid rendering when reflector is facing away

      if (view.dot(normal) > 0) return;
      view.reflect(normal).negate();
      view.add(reflectorWorldPosition);
      rotationMatrix.extractRotation(camera.matrixWorld);
      lookAtPosition.set(0, 0, -1);
      lookAtPosition.applyMatrix4(rotationMatrix);
      lookAtPosition.add(cameraWorldPosition);
      target.subVectors(reflectorWorldPosition, lookAtPosition);
      target.reflect(normal).negate();
      target.add(reflectorWorldPosition);
      virtualCamera.position.copy(view);
      virtualCamera.up.set(0, 1, 0);
      virtualCamera.up.applyMatrix4(rotationMatrix);
      virtualCamera.up.reflect(normal);
      virtualCamera.lookAt(target);
      virtualCamera.far = camera.far; // Used in WebGLBackground

      virtualCamera.updateMatrixWorld();
      virtualCamera.projectionMatrix.copy(camera.projectionMatrix); // Update the texture matrix

      textureMatrix.set(0.5, 0.0, 0.0, 0.5, 0.0, 0.5, 0.0, 0.5, 0.0, 0.0, 0.5, 0.5, 0.0, 0.0, 0.0, 1.0);
      textureMatrix.multiply(virtualCamera.projectionMatrix);
      textureMatrix.multiply(virtualCamera.matrixWorldInverse);
      textureMatrix.multiply(scope.matrixWorld); // Now update projection matrix with new clip plane, implementing code from: http://www.terathon.com/code/oblique.html
      // Paper explaining this technique: http://www.terathon.com/lengyel/Lengyel-Oblique.pdf

      reflectorPlane.setFromNormalAndCoplanarPoint(normal, reflectorWorldPosition);
      reflectorPlane.applyMatrix4(virtualCamera.matrixWorldInverse);
      clipPlane.set(reflectorPlane.normal.x, reflectorPlane.normal.y, reflectorPlane.normal.z, reflectorPlane.constant);
      const projectionMatrix = virtualCamera.projectionMatrix;
      q.x = (Math.sign(clipPlane.x) + projectionMatrix.elements[8]) / projectionMatrix.elements[0];
      q.y = (Math.sign(clipPlane.y) + projectionMatrix.elements[9]) / projectionMatrix.elements[5];
      q.z = -1.0;
      q.w = (1.0 + projectionMatrix.elements[10]) / projectionMatrix.elements[14]; // Calculate the scaled plane vector

      clipPlane.multiplyScalar(2.0 / clipPlane.dot(q)); // Replacing the third row of the projection matrix

      projectionMatrix.elements[2] = clipPlane.x;
      projectionMatrix.elements[6] = clipPlane.y;
      projectionMatrix.elements[10] = clipPlane.z + 1.0 - clipBias;
      projectionMatrix.elements[14] = clipPlane.w; // Render

      renderTarget.texture.encoding = renderer.outputEncoding;
      scope.visible = false;
      const currentRenderTarget = renderer.getRenderTarget();
      const currentXrEnabled = renderer.xr.enabled;
      const currentShadowAutoUpdate = renderer.shadowMap.autoUpdate;
      renderer.xr.enabled = false; // Avoid camera modification

      renderer.shadowMap.autoUpdate = false; // Avoid re-computing shadows

      renderer.setRenderTarget(renderTarget);
      renderer.state.buffers.depth.setMask(true); // make sure the depth buffer is writable so it can be properly cleared, see #18897

      if (renderer.autoClear === false) renderer.clear();
      renderer.render(scene, virtualCamera);
      renderer.xr.enabled = currentXrEnabled;
      renderer.shadowMap.autoUpdate = currentShadowAutoUpdate;
      renderer.setRenderTarget(currentRenderTarget); // Restore viewport

      const viewport = camera.viewport;

      if (viewport !== undefined) {
        renderer.state.viewport(viewport);
      }

      scope.visible = true;
    };

    this.getRenderTarget = function () {
      return renderTarget;
    };
  }

}

Reflector.prototype.isReflector = true;
Reflector.ReflectorShader = {
  uniforms: {
    'color': {
      value: null
    },
    'tDiffuse': {
      value: null
    },
    'textureMatrix': {
      value: null
    }
  },
  vertexShader:
  /* glsl */
  `
		uniform mat4 textureMatrix;
		varying vec4 vUv;

		#include <common>
		#include <logdepthbuf_pars_vertex>

		void main() {

			vUv = textureMatrix * vec4( position, 1.0 );

			gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );

			#include <logdepthbuf_vertex>

		}`,
  fragmentShader:
  /* glsl */
  `
		uniform vec3 color;
		uniform sampler2D tDiffuse;
		varying vec4 vUv;

		#include <logdepthbuf_pars_fragment>

		float blendOverlay( float base, float blend ) {

			return( base < 0.5 ? ( 2.0 * base * blend ) : ( 1.0 - 2.0 * ( 1.0 - base ) * ( 1.0 - blend ) ) );

		}

		vec3 blendOverlay( vec3 base, vec3 blend ) {

			return vec3( blendOverlay( base.r, blend.r ), blendOverlay( base.g, blend.g ), blendOverlay( base.b, blend.b ) );

		}

		void main() {

			#include <logdepthbuf_fragment>

			vec4 base = texture2DProj( tDiffuse, vUv );
			gl_FragColor = vec4( blendOverlay( base.rgb, color ), 1.0 );

		}`
};

THREE.Reflector = Reflector;
} )();
